SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d93519726e445307b499033f0e1d7e24a35da0569a293ea70467851545ab6a2' 
  AND token = 'wjliEwxnw0JTjevkx9HIjsPRocPaKNEIYWrWQiwG8ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}